Packaging



0d; 30, 1962 R. L. DREYFUS 3,060,655

PACKAGING Filed Nov. 7, 1958 4 Sheets-Sheet 1 FIGJ8.

FIG. 1. i

22 n so 710 4 3 32 6 Y IN VENTOR 9o ZerZZ, .Drey/as ATTORNEYS Oct. 30,1962 R. 1.. DREYFUS 3,060,655

PACKAGING Filed Nov. 7, 1958 4 Sheets-Sheet 2 'INVENTOR Po Zer Z1.2787/5 Oct. 30, 1962 DREYFUs 3,060,655

PACKAGING Filed Nov. 7, 1958 4 Sheets-Sheet 3 All!!! i INVENTOR F0 5 7'i L Dreyfus ATTORNEYS Oct. 30, 1962 R. DREYFUS 3,060,655

PACKAGING Filed Nov. 7, 1958 4 Sheets-Sheet 4 FIG..9.

INVENTOR F0 ZerZL. Dr f gW MW ATTORNEYS Unite This invention relates toa novel method and apparatus for shrinking a biaxially oriented olefinpolymer and to goods contained in or confined by such polymer.

It is an object of the present invention to provide a method forapplying a protective cover over the open side of a container.

Another object is to provide an apparatus suitable for forming ashrinkable polymer film into a cover for a container, folding the edgesagainst the sides of the container and shrinking portions of the polymerfilm to form the cover.

A further object is to form an elastic edged cover for dishes and thelike, said cover being thickened in the edge portion.

An additional object is to provide a cover from a plastic film whichwill have a tab to assist in removing the cover.

Yet another object is to improve the bond of shrinkable irradiatedpolyethylene covers to containers made of glass, paper or thermosettingplastic.

A still further object is to provide complete encapsulation of objectsutilizing a shrinkable irradiated polyolefin tubing.

An additional object is to partially encapsulate objects usingshrinkable irradiated polyolefin tubing or sheet film.

A further object is to control the shrink around an object of a tube ofshrinkable polymer so that the open ends of the tube can be directed tothe back of the object.

Additionally, it is an object of the present invention to reduce theamount of material required in an overwrap package.

Still further objects and the entire scope of applicability of thepresent invention will become apparent from the detailed descriptiongiven hereinafter; it should be understood, however, that the detaileddescription and specific examples, while indicating preferredembodiments of the invention, are given by way of illustration only,since various changes and modifications within the spirit and scope ofthe invention will become apparent to those skilled in the art from thisdetailed description.

These objects are attained in the manner subsequently describedutilizing heat shrinkable irradiated polyolefins, more particularly,heat shrinkable, irradiated polyethylene and heat shrinkable irradiatedpolypropylene.

Referring to the drawings:

FIGURE 1 is a side elevation of a preferred apparatus for heat shrinkinga cover on a container;

FIGURE 2 is a side elevation of an alternative device for heat shrinkinga cover on a container;

FIGURE 3 is a sectional view taken along the line 33 of FIGURE 2;

FIGURE 4 is a side elevation of another device suitable for heatshrinking a cover on a container;

FIGURE 5 is a perspective view showing the encapsulation of a pair ofscissors;

FIGURE 6 is a side elevation partially in section taken during a laterstage of the encapsulation;

FIGURE 7 is a vertical section showing the partial encapsulation of aroll of paper;

FIGURE 8 is a top elevation of a cylindrical container spirally wrappedwith the shrinkable polyolefin;

FIGURE 9- is a perspective view of a box of candy Patented Oct. 30, 1962being placed in a tube of heat shrinkable, irradiated polyethylene;

FIGURE 10 is a side elevation of the candy box showing a subsequentstage utilizing localized heating;

FIGURE 11 is a vertical section of the encapsulated candy box near theend of the shrinking process;

FIGURE 12 is a bottom plan view of the encapsulated candy box;

FIGURE 13 is a sectional view of an alternative method of forming acover around a container;

FIGURE 14 is a sectional view of the cover at the completion of theprocess in FIGURE 13;

FIGURE 15 a vertical section showing the partial encapsulation of a ringgasket;

FIGURE 16 is a plan View showing the formation of an overwrap;

FIGURE 17 is a side elevation showing the sealing of the overwrap ofFIGURE 16; and

FIGURE 18 is a vertical section of a container having a heat shrunkcover thereon.

In the specific examples below there was employed heat shrinkableirradiated, biaxially oriented polyethylene, specifically Alathon 14,molecular weight of 20,000 and density of 0.916, which had beenirradiated to an extent of about 12 megarad and then biaxially stretched350% longitudinally and 350% laterally. The irradiated polyethylene hada shrink energy of about p.s.i. in both directions.

Referring more specifically to FIGURE 1 of the drawings, there isprovided an apparatus 2 for selectively shrinking irradiatedpolyethylene film to provide an elastic edged cover for dishes. Inproviding such covers there is the problem of holding the cover film inplace and folding the edges down evenly against the sides of thecontainer and then shrinking them in that position. To even out anywrinkles, the cover film can be finally heated slightly, if desired. Theapparatus of FIGURES 1 and 2 are eminently suited to solve the problemoutlined above.

The apparatus 2 comprises a hot air blower 4 and a turntable 6 mountedfor rotation on support 8. A truncated conical container 10, e.g., a waxcoated paper container filled with cheese, is positioned on theturnab-le and an approximately circular film 12 of the irradiated biaxially oriented polyethylene of somewhat larger diameter than the openend 14 of the container was positioned over the opening.

Above the turntable 6 is positioned a diaphragm holder 16 of largerdiameter than the container. The diaphragm holder is mounted forrotation concentrically with turntable '6 on support 18.

The diaphragm also is connected to lever 20 which can raise or lower thediaphragm holder to the idle or working condition as is required. Thediaphragm holder is cylindrical and has an inner flange 22 at its lowerend. Secured to the diaphragm holder is a diaphragm or sponge pad 24which is flat in the non-compressed state. The diaphragm has a flathorizontal upper section 216, a middle section 28 extending outwardlyand downwardly and of a conical shape and an outwardly extending lowerportion 30 which is connected to the inner flange 22.

In operating according to the invention the container 10 is positionedon the turntable 6. The film 12 of irradiated biaxially orientedpolyethylene from 0.5 to 5 mils, e.g., of 3 mil thickness, is thenpositioned over the top of the container. The lever 20 is then lowereduntil the upper portion 26 of diaphragm 24 engages the film. The

diaphragm not only holds the film in place but it also evenly bends downthe over-lying edges 32 of the film. The hot air blower is then startedas is the turntable. The hot air forces the film in place against thesides 34 of the container while at the same time the hot air alsoshrinks the film. As a result the film forms a thickened edge or bead 37as shown in FIGURJE 18 around the lip of the container. This thickenededge is usually about to times as thick as the film itself. As a result,an elastic edged cover for the container is formed. The cover can beremoved to open the container and then can be again applied as a coverfor the container due to its elasticity.

In order to even out any wrinkles formed in the cover film, it can beheated slightly while on the turntable.

The use of the turntable insures that the cover is evenly heated andconsequently that there will be uniform shrinkage to form a smooth andattractive sealing edge on the film.

In FIGURE 4 there is shown a special nozzle 110 which has beensuccessfully employed for sealing the irradiated biaxially orientedpolyethylene over the top of pie plates, cheese tubs, glasses, cups andthe like. The nozzle of FIGURE 4 can be used with any commerciallyavailable hot air source. The nozzle 110 comprises a cylindrical neck112 which can be split as at 1 14 to pinch-fit a fiameless blow torch.The neck 112 ends in a metal cone 116. At the lower end of the conethere are four narrow supports 118 for metal disc 120. Adhered to themetal disc 120 is a soft silicone or other heat resistant sponge 122.The sponge preferably has a 30 durometer hardness and is apolydimethylsiloxane, although other silicone sponges can be employed. Ametal inverted truncated cone 124 terminating in an inner flange 126also depends from the lower end 128 of the cone 116. Above the metaldisc 120 there is provided a foamglass insulator 130 to protect againstundesired heating of the container 132 to which is applied theirradiated biaxially oriented polyethylene film 134. The container 132is supported on stand 136. The film is shaped to the desired covercontour as described in connection with FIGURE 1. Heating isaccomplished, however, by the hot air which passes through the nozzleand emerges at the lower end 128 of the cone along the periphery thereofand thence to inverted cone 124 where it contacts the formed cover andshrink seals it to the container. This unit has been employedsatisfactorily at a gas temperature of 500 F. although othertemperatures can be employed so long as they are high enough to shrinkthe polyethylene.

In place of the turntable and single position blower there can be usedother devices to insure uniform heating. For example, as shown inFIGURES 2 and 3, the blower and turntable can be supplanted by anannular ring 36 supported on frame 40 and having a series of openings 38placed to direct heated air introduced via line 42 upward to bereflected from the diaphragm in a manner to push the film against thecontainer sides While shrinking the edges to form the finished covershown in FIGURE 4. It will be appreciated that instead of heated airthere could be employed steam, hot Water or other heated fluid.

The diaphragm and associated heating apparatus can be placed on aconveyor to either travel with the product during the application ofheat or to have the conveyor index under a fixed application point.

In a continuous process, for example, a dispensing device can beprovided over the conveyor in advance of the unit to place a circulardisc or square of film over each container as it passes under thedispenser. A small traveling band of tape or an air curtain can be usedto hold the film in place as the conveyor travels ahead. After shrinkingthe film to form the bead, either hot air from the annular ring (orrectangle) as it rises from contact or from a separate hot air blowercan be used to elimininate any wrinkles from the surface of the package.While the film which forms the thickened edge is substantiallycompletely shrunk, there is virtually no shrinkage of the protectivefilm over the opening 14 of the container.

The process can be carried out utilizing a substantially invertedapparatus wherein hot air from orifices in a table top blow the filmupward and inward to effect the seal. Alternatively, the film andinverted dish can be placed on a depressable pad and pushed downwardinto a chamber of heated fluid which would float the film upward andinward. In this procedure preferably the immersion is controlled so asnot to let the heated liquid flow over the edge of the film untilshrinkage is accomplished.

The film cover pressure pad 24 can be applied to the film in a chamberwhich has been filled with an inert gas, e.g. helium, argon or nitrogen,or in a vacuum chamber. Shrinking and sealing can then be accomplishedto maintain this controlled atmosphere within the container beingsealed.

When a square of film is positioned on a round container opening thesubsequent shrinking provides small, unobtrusive tabs which aid inremoving or reapplying the cap.

The cap or cover has been found to seal tightly by its own tension inmost cases. An especially good bond can be obtained by coating theoutside of the container in the sealing area with wax or with otherthermoplastic material.

The apparatus shown in FIGURES l-4 is particularly useful in preparingclosures, e.g. milk bottle hoods, covers for pie plates, trays, meat pieplates, TV dinner trays, jars, cans or jelly tumblers, particularlythose having a flared or lip-type top edge. It is likewise useful incovering containers for ice cream, potato salad, cottage cheese or otherfoods in plastic or coated paper or metal, e.g., aluminum, containers.

The present invention is also useful in the complete encapsulation ofobjects using tubing or partial encapsulation using tubing or sheet filmas well as in the formation of lids or covers as previously set forth.

To completely encapsulate an object, e.g., a scissors 50 in FIGURE 5, itis placed in a slightly over-size tube 52 of the irradiated high shrinkenergy polyethylene. The tube should be about 4 to 6" longer than theoverall scissors length. Then, first one open end 53 of the tube isheated and shrunk back to tape dimensions at 54 and then the other openend 55 is shrunk back to tape dimensions at 56. The heating can beaccomplished with radiant heater 58, FIGURE 6, or with hot air as bydrier 4, FIGURE 1, or by nozzle type drier of FIGURE 4. Then heat isapplied over the entire tube to shrink the same as at 60 and to forceout most of the air. The ends are reheated and when hot are pinched offto form a seal. Then the package is cooled to give a completelyencapsulated sclssor.

Partial encapsulation can be accomplished, for example, by placing aroll of paper 62 on a core 64 within a tube 66 of irradiated high shrinkenergy polyethylene. The ends of the polyethylene are folded down andshrunk and heat subsequently applied to the rest of the package, e.g.,with a hot air drier to encapsulate the roll of paper while the ends 68and 69 of the core stick out as shown in FIGURE 7.

Using a sheet of irradiated high shrink energy polyethylene rather thana tube, it is also possible to encapsulate objects as is shown in FIGURE8. A sheet 70 of the polyethylene is spirally wrapped around cylindricalcontainer 72. Opposite ends 74 and 76 of the sheet are heated, e.g.,with the aid of radiant heater 73, and thus shrunk to secure thePackage. Then the remaining surfaces of the polyethylene sheet are heatshrunk around the cylinder to complete the encapsulation procedure. Theapplication of heat will partially seal the overlap.

It is possible to control the application of heat in the shrinking ofirradiated high shrink energy polyethylene tubing so that the open endsof the tube can be directed to the back or any other desired part of thecontainer so that they are in effect concealed and do not depart fromthe attractiveness of the packaged product. This form of the inventionis illustrated in FIGURES 9-12 wherein heat is selectively applied todirect the open ends of the tube to the back of the package. Referringmore specifically to FIGURES 9-12, there is provided a tube 78 ofirradiated high shrink energy polyethylene having open ends 80 and 82. Aheart-shaped candy package 84 is inserted in the tube 78. The candypackage has a top 86, bottom or back 88, and sides 90. Heat is thenconcentrated on the back 88 rather than on the entire package with theaid of hot air heater 92. As a result, shrinkage occurs primarily in theback with the net result that the film is relatively thick on the backand relatively thin in the front. Additionally, as shown in FIGURES 11and 12, the original openings in the tube end up on the back of thepackage in relatively closespaced relation compared to their originalpositions and the openings can be covered by a label. Due to theshrinkage in the tubing a tight fit over the package results. If thereare any wrinkles in the front or top of the package, they can be removedby briefly passing the hot air heater over the front of the package. Theend result is an attractive package in which the original open end-s ofthe tubing are effectively concealed. In fact, anyone who is notfamiliar with the manner of applying the polyethylene cover would notrealize that the candy box had been covered with tubing.

As previously set forth, the present invention is especially adapted toplace a protective polyethylene film on lids or covers. This form of theinvention is also illustrated in FIGURES l3 and 14. Thus, a form or ring94 for making a lid or cover is placed top side down on a piece ofirradiated high shrink energy polyethylene film 96. The edges of the lid94 and the corresponding area of the polyethylene film are restrained bymeans of ring 98. The free polyethylene film 99 on the back 100 of thelid is heated with hot air heater 92 to shrink and thicken thepolyethylene at 102 as shown in FIGURE 14. The restraining ring acts tocontrol the shrinkage since shrinkage does not take place under it orbeyond. In order to remove wrinkles from the polyethylene film, thefront of the lid can be heated briefly as can the sides and the areaunder the ring. In similar fashion the polyethylene film 104 can beshrunk around gasket 106 to form a thickened sealing area 108' at theback as shown in FIGURE 15.

The present invention can likewise be used to cover only one surface andthe sides of a package, the back surface being sealed only at the fourcorners as is illustrated in FIGURES l6 and 17. As an illustration ofthis procedure a box 5" x 8" x 1%" was packaged using an irradiated highshrink energy polyethylene film 9 /2" wide by 12%." long. Thesedimensions were obtained by utilizing as the width the box width+2 timesthe box heightj+2 inches, and as the length, the box length+2 times thebox height+2 inches.

The box 140, top side 142 down, was centered on the polyethylene film1-44 with the long side 146 of the box parallel to the long side of thefilm. One opposite pair of film edges, e.g. the two long edges 150 and152, were folded over the box.

Then the second pair of film edges, namely the short edges 154 and 156,were folded over the box. At the four corners these edges overlapped.The box 140 was then inverted on Teflon 158 (polytetrafluoroethylene)covered hot plate .160. The hot plate was set at about 300- 325 F. andweight 162, biased by spring 164, was pressed down firmly on theoverlapping edges to heat the film uniformly. The film sealed at thefour corners and shrunk along the borders with a resultant increase ingage and tightness. The film should be cooled while the film is stillbeing restrained.

Normal overwrapping, e.g. the diaper wrap, requires 14" x 14" (196 sq.in.) or larger of polyethylene film. The present procedure thus resultsin a saving of 40% or better in material required.

In general, there is employed in the invention polyethylene film ortubing which has been irradiated to an extent of 2 to megarad,preferably 6 to 20 megarad. The irradiation can be accomplished inconventional fashion, e.g. by the use of a high voltage resonanttransformer, such as the 2,000,000 volt General Electric transformer, orsimilar transformers of 50,000 to 50,000,000 volts or a Van de Graaifelectron generator. In addition to the use of electrons there can beemployed beta rays, gamma rays, e.g. by employing cobalt 60, etc. Therecan be employed any of the irradiation procedures disclosed in Bairdapplication, Serial No. 713,848, filed February 7, 1958, now Patent3,022,543, issued February 27, 1962, for example. The entire disclosureof the Baird application is hereby incorporated by reference.

The biaxial orientation is normally carried out to an extent of 100 to700% longitudinally and 100 to 900% laterally. The biaxially stretchingcan be carried out by blowing irradiated polyethylene tubing asdisclosed in the Baird application. The irradiated biaxially orientedpolyethylene prepared by such a procedure has a high shrink energy, e.g.100 to 500 p.s.i.

There can be employed as the starting polyethylene for the irradiationprocedure high, low or medium density polyethylene prepared by low orhigh pressure technique. The starting polyethylene can have a molecularweight of 7,000 or 12,000 or 19,000 or 21,000 or 24,000 or 35,000 oreven higher.

In place of irradiated polyethylene there can be employed irradiatedpolypropylene.

What is claimed as new is:

1. The method of encapsulating a container having a front and a back ina single thickness, preformed tubing of irradiated, biaxially oriented,high shrink energy polyethylene comprising placing said container insaid tubing, selectively heating the portion of the side Wall of thetubing adjacent the back of the container to shrink said portion of thetubing only and to force the open ends of the tubing to the back of saidcontainer.

2. A method according to claim 1 wherein the front of the container isheated briefly to remove wrinkles in the tubing.

3. A method according to claim 1 wherein the contained is a heart-shapedbox having sides containing candy, the box is placed in the tubingsidewise and the selective heating is sufficient that the ends of thetubing are in relatively much closer spaced relation than their originalspaced relationship prior to shrinking.

4. The method of encapsulating an object in a tubing of a high shrinkenergy plastic, said object being threedimensional and having at leastone substantially flat surface comprising positioning the object in thetubing, selectively heating substantially only the portion of the sidewall of the tubing covering said substantially fiat surface to shrinksaid portion thereof only and to force the open ends of the tubing todesired closer position that the original spacing of such open ends,said position being on said flat surface.

References Cited in the file of this patent UNITED STATES PATENTS1,929,217 Rosen Oct. 3, 1933 2,042,304 Glunz May 26, 1936 2,385,257Cavallito Sept. 18, 1945 2,441,227 Pineles May 11, 1948 2,597,830 WebbMay 20, 1952 2,638,724 Harvey May 19, 1953 2,668,403 Rumsey Feb. 9, 19542,744,669 Ashe et a1. May 8, 1956 2,754,959 McCarty July 17, 19562,775,082 Vogt Dec. 25, 1956 2,842,910 Reed July 15, 1958 2,779,681 Sellet a1. Jan. 29, 1959 2,878,628 Curry Mar. 24, 1959 2,934,865 PfeifferMay 3, 1960

